The present invention relates to a device for holding two structural parts in a spaced relationship with respect to each other.
One such device operates on the basis of the principle described in European Patent Application 0 176 663. The device consists of a support part which can be brought into a position secured against rotation with the first part. The helical engagement surface of a rotary drive part rests on a helical engagement surface of the support part. The rotary drive part can be turned with respect to the support part. In such case, the two engagement surfaces slide on one another so that, as a result of their helical shape, the spaced-apart relationship of those two end surfaces of the support parts which face away from each other are moved apart from each other. Support part and rotary drive part lie one behind the other in axial direction, a screw which extends coaxial to the axis passing through an opening in the device. The screw has a thread of a direction opposite that of the engagement surface. In case of a right-hand screw, the engagement surface is developed as a left-hand winding. Upon being screwed into the rotary drive part, the screw, as a result of a frictional engagement of its external thread in the hole in the rotary drive part carries the rotary drive part along with it so that the engagement surfaces slide on each other and the end surface of the rotary drive part can move until it comes against the second structural part so that the distance between the two structural parts is filled up. Further turning of the screw then no longer leads to the carrying along of the rotary drive part so that the screw can be screwed in completely and then be screwed, on the opposite side, into a corresponding internal thread of the second structural part so that the two structural parts are fastened to each other. In the device of this type, support part and rotary drive part are connected to each other as a complete assembly unit. This is effected, for instance, in the manner that the parts are snapped onto one another by a spring or other means. For the preassembly, it is furthermore necessary that the support part be brought into a temporary fastening position with respect to the first structural part. For this, hook-shaped extensions are used by which the support part can be snapped onto the first structural part.